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From |
"Jesper Lindhardsen" <JESLIN01@geh.regionh.dk> |

To |
<statalist@hsphsun2.harvard.edu> |

Subject |
RE: st: age: factor variables may not contain noninteger values |

Date |
Wed, 9 Nov 2011 13:34:06 +0100 |

Hey there, I agree with both of you. However, since Lars wanted to use age as a categorical variable , this implies reducing the age information to an interval. In this sense, round will provide the -.5 to +.5 interval..... which makes Lars 40 already ;-) BW, Jesper -----Original Message----- From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Nick Cox Sent: 08 November 2011 20:40 To: statalist@hsphsun2.harvard.edu Subject: Re: st: age: factor variables may not contain noninteger values All that said, as age as an integer usually means "age last birthday", I am surprised that -round()- is regarded as the answer. I would put my foot down for -floor()-. For example, I am 19 and will not be 20 until next birthday. Nick On Tue, Nov 8, 2011 at 7:29 PM, Lars Folkestad <lfolkestad@health.sdu.dk> wrote: > Thank you for that jesper. It sure did the trick. > lars > > Den 08/11/11 13.17 skrev "Jesper Lindhardsen" <JESLIN01@geh.regionh.dk>: > >>Hi Lars, >> >>Try >> >> >>g new_age= round(age_var,1) >> >> >>HTH, >> >>Jesper >> >>-----Original Message----- >>From: owner-statalist@hsphsun2.harvard.edu >>[mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Lars >>Folkestad >>Sent: 08 November 2011 12:14 >>To: statalist@hsphsun2.harvard.edu >>Subject: Re: st: age: factor variables may not contain noninteger values >> >>This helps a lot. >>Thank you. >> >>But i have a question about the second point. >>Is there a quick and easy way to round the age to the nearest integer >>value? I could use the floor / ceil functions, but some of the ages >>Should be rounded up and some should be rounded down. >> >>lars >> >>Den 08/11/11 11.40 skrev "Maarten Buis" <maartenlbuis@gmail.com>: >> >>>On Tue, Nov 8, 2011 at 11:13 AM, Lars Folkestad wrote: >>>> I am trying to investigate the interactions between age and a >>grouping >>>>variable in a regression model, using this code: >>>> >>>> xi: regress Var1 age##i.group >>>> >>>> Var1: is a continuous variable >>>> Age: is a continous variable / float >>>> >>>> When i run the code i get the following error message: >>>> age: factor variables may not contain noninteger values >>> >>>First, you are mixing -xi- and factor variable notation. You should >>>just leave the -xi:- prefix away. >>> >>>Second, in most surveys I am aware of age will be measured in whole >>>years. In those cases age should only contain integer values and this >>>error message means I made an error while preparing the data. This is >>>true regardless of how the data is stored. However, this is not >>>necessarily an error, you could have fractional age if you had for >>>instance exact birth dates and exact dates at which events of interest >>>happen. Alternatively, I may have standardized age or rescaled it so >>>it is measured in decades rather than years. However, in the latter >>>two cases I would have created new with different variable names >>>(probably z_age and age_d). So I would check whether non-integer age >>>would make sense given the way your data was collected. >>> >>>Third, whether there is an error or not you probably want -regress >>>var1 c.age##i.group- i.e. tread age as a continuous variable and not >>>as a set of dummies. >>> >>>Hope this helps, >>>Maarten >>> >>>-------------------------- >>>Maarten L. Buis >>>Institut fuer Soziologie >>>Universitaet Tuebingen >>>Wilhelmstrasse 36 >>>72074 Tuebingen >>>Germany >>> >>> >>>http://www.maartenbuis.nl >>>-------------------------- >>> >>>* >>>* For searches and help try: >>>* http://www.stata.com/help.cgi?search >>>* http://www.stata.com/support/statalist/faq >>>* http://www.ats.ucla.edu/stat/stata/ >> >> >>* >>* For searches and help try: >>* http://www.stata.com/help.cgi?search >>* http://www.stata.com/support/statalist/faq >>* http://www.ats.ucla.edu/stat/stata/ >> >>* >>* For searches and help try: >>* http://www.stata.com/help.cgi?search >>* http://www.stata.com/support/statalist/faq >>* http://www.ats.ucla.edu/stat/stata/ > > > * > * For searches and help try: > * http://www.stata.com/help.cgi?search > * http://www.stata.com/support/statalist/faq > * http://www.ats.ucla.edu/stat/stata/ > * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/ * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**RE: st: age: factor variables may not contain noninteger values***From:*Nick Cox <n.j.cox@durham.ac.uk>

**References**:**RE: st: age: factor variables may not contain noninteger values***From:*"Jesper Lindhardsen" <JESLIN01@geh.regionh.dk>

**Re: st: age: factor variables may not contain noninteger values***From:*Lars Folkestad <lfolkestad@health.sdu.dk>

**Re: st: age: factor variables may not contain noninteger values***From:*Nick Cox <njcoxstata@gmail.com>

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